We like the visual design on "Draw Something" (you can google search for examples), which we view as a combination of minimalist and playful colors.
We prefer "whole screen" vertical scrolling, rather than any type of compartmentalized sub-regions. We'd like to have a single fun but traditional "application title bar" at the top of the home-screen, and the rest of the information panel should vertically scroll as one large panel.
We like apps which have some kind of custom background image, as we feel it creates "depth". Whether that image scrolls with the UI, or remains stationary is open to the design.
One important element of our apps is that we show user-authored drawings on the home screen (wheras draw-something only shows profile images). Because drawings are multi-colored, they can really clash and compete with the UI colors, and the colors of other drawings. Therefore, we recommend exploring monochrome techniques, either for the UI, or mono-chroming of the drawings displayed on the home-screen. (see attachment for examples of drawings)
(see document for screenshots of working prototype)